Specific gravity indicator for drilling mud



J. WAR EN; JR 2,373,795

April 11, 1945.,

SPECIFIC GRAVITY INDICATOR FOR DRILLING MUD 4 Sheets-Sheet l N Filed May6, .1938

I I IIIIIIIIIIIIIFJ Apl'il 1945- J. B. WARREN, JR 5.

SPECIFIC GRAVITY INDICATO RFOR DRILLING MUD v Filed May 6, 1958 4 Sheets-She'et 2 A fil 17, 1945.

'J. B. WARREN, JR

SPECIFIC GRAVITY INDIGATOR FOR DRILLING MUD 4. Sheets-Sheet 3 Filed llay6, 193a J. B.WARREN JR.

April 11945 J. B. WARREN, JR, 2,373,795

' SPECIFIC GRAVITY INDICATOR FOR DRILLIKG- IUD l iled llay 6, 1938 4Sheets-Sheet 4' I Patented Apr- John B. Warren, In, Houston, Tex.Application May- 6. 1938, Serial No. 206,327 9 Claims." (01. 73-32) Theinvention relates to a means for determining the specific gravity ofaliquid and is'particularly adapted for use in determining the specificgravity of drilling mud used in the rotary method of drilling wells.

In the rotary method of drilling wells a circulation of slush is pumpeddownwardly through the drill stem and discharged therefrom adjacent thecutting edges of the bit. This circulation of mud has many functionssuch as to carry the cuttings away from the bit and keep the bit cool aand in some instances to wall up the formations which have beenpenetrated and to maintain such formations against caving. It is usual,therefore, to have this slush. made up of clays suspended in water orother liquids and there are many ingredients which .are used to obtaindrilla ing muds having various specific .characteristics.

In some instances it is desirable to have the mudof greater specificgravity in order to prevent caving of the formation and to create a highunit area pressure on theformation to overcome the natural pressuresencountered in the formation. In other instances it is desirable to have'a mud with a greater viscosity so that it will carry cut-'- tings fromthe well bore without permitting the cuttings to settle out of the mud.In other instances itis desirable that the mud have greater slimingqualities, so that it will not create an undue-frictional resistanceduring its circulation into and out of the well bore and, in still otherinstances, it is. desirable to have a mud from fwhichthe gas can bereadily expelled so that there will be no gas cutting or reduction inspa-- cific gravity of the mud, due to the presence of gas therein, andwhile in still other instancesthe --point of inlet.

Another object of the invention is to provide an arrangement whereby thespecific gravity of a body of liquid may be determined as a functionof'the differential pressure required to inject two spaced streams offluid into a body of the liquid.

Still another 'object of the invention is to provide a bubble glass foruse with a device for in troducing a flow of fluid into a body of hquid.Still another object of the invention is to provide a device forlubricating the inflow of fluid into a ,body of liquid to offsetevaporation at the Still another object of the invention is to providean apparatus for determining specific-grav ities, which apparatus willreceive the body of the liquid, record the specific gravity thereof anddischarge the body .of the liquid inan automatic sequence of periodicoperations.

Still another object of the invention is to provide a mechanism forintroducing fluid under pressure in order to determine the specificgrav-- ity of'a'body of liquid, which mechanism will operatecontinuously and automatically.

Still another object of the invention is to provide a' particular typeof bubble glass for deter- --mining the rate of flow of a fluid so thatsuch mud may become diluted by the inflow of water or other materialsfrom the formation in the well bore. v

During the drilling operation as the drill bit penetrates variousformations the characteristics of drilling mud being introduced into thewell bore must be changed in order to cope with the. circumstances whicharise and with this in mind it is desirable to determine the specificgravity of the mud which is being discharged from the well bore at quitefrequent intervals because any change in the specific gravity may havedisastrous results depending upon the conditions which are beingencountered.

With the foregoing-in-nfind it is one of the objects of the presentinvention to' provide a means for periodically determining the specificgravity-ofthe flow of mud as it emerges or enters the well bore.

glass may be tilted or turned without discharging the indicating liquidtherefrom.

Still another object is to provide a tained compact device which may bereadily connected to determine the specific gravity of a well drillingfluid.

Other and further objects of the invention will be readily apparent whenthe following description is considered in connection with theaccompanying drawings wherein;

Fig. 1 is a side elevation of the upper portion'of the mechanism whichmay be used in practicing the invention. I

Fig. 2 is a vertical sectional view through the plunger apparatus forcontrolling the inflow and outflow of the liquid the specific gravity ofwhich is being measured.

- Fig. 3 is a side elevation taken at right angles to the view of Fig. 1v

Fig. 4 is a top plan view looking down on the apparatus of Figs. 1 and3.

Fig. 5 is a section taken on the line 5-5 of Fig. 3. p 7

Fig.6 is a sectional view of thecontrol valve.

Fig. 7 is a section of the valve taken on the line I 1- 1 of Fig. 6.

Fig. 8 is a vertical sectional view through one of the bubble gaugestaken on the line 8-4 of self con- Fig. 11 with certain of the portionsbroken away to illustrate the arrangement of the parts.

The device is particularly adapted for use at a drilling rig to measurethe specific gravity of the drilling mud, oil or water.

The invention contemplates that a charge of the drilling fluid used inthe rotary method of drilling wells will be trapped. A flow of the fluidunder pressure will be introduced into this trapped body of liquid atpredetermined spaced elevations and the pressure required to sointroduce the flow of fluid under pressure will be different for the twodifierent elevations. If the specific gravity of the liquid varies thedifferential pressure required to introduce the fluid under pressure atthe spaced elevations will vary in direct proportion thereto so that theentire mechanism herein disclosed is for the purpose of automaticallyintroducing and determining this differential pressure In the severalfigures a return or flow line 2 has been illustrated and this pipe maybe either the usual return line from the well to the slush pit in whichthe mud is retained, "or it may be abypass therefrom, as circumstancesmay require. In either instance, however, it isintended that there willbe a flow of drilling fluid from the well passing through this pipe 2.

.The apparatus for determining specific gravity is indicated generallyat 3 and is arranged about the pipe 2 so that a specimen of the liquidin the pipe may be deposited in the apparatus. The mechanism forobtaining such sample is best seen in Figs. 2 and 12. In Fig. 12 acontainer 5 of any desired size may be positioned about the pipe 2 insuch a manner that a flow of liquid discharging from the opening 6 willflow into the container 5.

The container 5 is of suflicient height so that a predetermined volumeof drilling mud will be trapped therein. In order to open the pipe 2andv admit a flow of drilling mud into the container a top valve 8 hasbeen provided. This valve is arranged tomove upwardly into the opening 6to close the opening and to movedownwardly out of the opening to admit aflow of mud into the container. This valve 8 is carried by a valve rod9, which is guided through a support H! exranged to close the dischargeoutlet I2 in the base of the tank. As seen in Fig. 12, the bottom valveis closed and the top valve is open.

It seems obvious that with the valves in the position of Fig. 12 a flowof liquid will pass into the container 5 and be trapped therein, whereasIn this liquid to be measured shall be controlled auto- 'matically andthat the. determination of the specific gravity of the charge orspecimen of liquid will also be automatically determined. With this inmind a float l3 has been provided near the base of the tank and anotherfloat l4 near the top of the tank. The bottom float I3 is connected bymeans of spaced rods 5, best seen in Figs. 11 and 3, to a link portionl6, which link is slidable relative to a bolt 11 carried by the valvearm I8, which arm serves to actuate the control valve 19. It seemsobvious that as the float [3 moves upwardly there will be a tendency tolift the link l6 and slide it upwardly relative to the bolt H from theposition shown in Fig. 3.

The float I3 is guided by the valve rod 9 and will be stopped in-itsupward movement by the guide arm l0 and this arm is so spaced relativeto the float that the link 16 will not quite reach its upward limit ofmovement when the arm I8 is in the position shown in Fig. 3, so thatwhile the float I3 may move upwardly on an accumulation of liquid in thecontainer it will not move upward a sufficient distance to affect thearm l8 when it is in the position shown in Fig. 3.

The float M on the other hand is slidably mounted in a cage 20 and isarranged to' rest upon a stop 2| when it is in the position shown inFig. 3. This float M has a member 22'which has a slot 23 thereinarranged to slide relative to the pin'24, which projects from the arml8. In the position shown in Fig. 3 any upward movement of the float Mwill tendto carry the arm 18 up ward with it by virtue of the pin 24contacting the bottom of the slot 23.

and simultaneously the valve I I opens and allows the liquid from thechamber to discharge. As the liquid settles away'from the float l4 itwill move downwardly. As the elevation of the liquid in the containercontinues to fall it will pass the float l3 and allow the float andtherods D5 to move downwardly. In order to move the lever 18 down andreverse the movement of the piston 31 as hereinafter described, the linkI6 will engage the bolt I1 and bring the lever I8 down when thecontainer is substantially empty. It is of advantage to flow the sampleinto the container from the top as it has been found in practice that amore uniform sample is thus obtained. The container 5 will thus beeither filling or emptying I in a continuous but periodic manner.

. tending from the-side of the container 5. 'This valve rod carries abottom valve II, which is ar- I and the valves 8 and \H is best seen inFigs. 2

when the valverod 8 and the valves 8 and H The mechanism for operatingthe valve rod 9 and 3 and comprises a cylinder 26 which may be mountedupon a suitable section of the pip 2, or may be otherwise mounted sothat it is in alignment with the frame 21 about the pipe 2.

This frame 21, as best seen in Fig. 3, constitutes a cross piece 28 andthe spaced rod members 29. These rods straddle the pipe 2 and thecylinder 26 and extend down into the container 5 where the cross piece30 surrounds the valve rod 9. When this framework is moved to its upperposition itwill raise the valve rod 9 and the valves 8 and H, but whenit is moved downwardly, as seen in the drawings, it allows the valve IIto seat and close the container. A piston 3|is connected to the rod 32which is slidable within the cylinder 25 and is connected to the crossbar 28.

through the tour-way cross 53. In this manner A pipe 34 enters thecylinder 25 to introduce and allow the escape of fluid under pressure tomove the piston 3| and a similar pipe 35 is connected to the base of thecylinder. It seems obvious that when pressure is introduced below the.piston it will rise and carry with it the frame 21 to raise the valverod and open the container by 2 opening the valve whereas when thepiston m'oves downwardly the frame 21 will move downwardly and the valveH will close and the valve 3 will open.

In order to control the flow of fluid under pressure in the pipes 34 and35, the control valve I9 is arranged for operation by means of the leverIt. The detailed construction of .this valve is' best seen in Figs. 6and 7 wherein the valve body '40 has a plurality of passages 4| thereinwhich lead to a central chamber-42. A pipe 43 furnishes a supply offluid under pressure tothe control valve l9 and this pressure isintroduced into the chamber 42. A valve member 44 is movable in thechamber by means of the lever I8 previously dein Fig. 7 and has theoutstanding wings 45 therein which form a seal with the periphery of thechamber 42. In the position shown .inFig. '7 fluid is entering thepipe43 and flowing out of the valve from the pipe 34; Fluid is alsoentering" through the pipe 35 on the opposite side of .the valve anddischarging from the pipe 48. The pipes 34 and 35, as previously pointedout, are connected to the top and bottom, respectively, of the cylinder25 so that with the valve in the position shown in' Fig. 7 pressureisbeing applied on top of the piston to force it downwardly and thatfluid which was in the cylinder 25 below the piston is being allowed todischarge through the the atmosphere, as seen in Fig. 2. a

It seems obvious that as the lever l8 moves to its upper positionthe'valve member 44 will turn a suflicient amount 'so that the wingswill pass over the openings to which the pipes 34 and 35 are connected.If this valve member moves approximately from the position shown inFig.7,

then the pressure pipe 43 will be connected to 'the pipe 35 and pressurewill be introduced under 5 the piston 3| in the cylinder and at the sametime any pressure which was above the piston will escape through thepipe 34 and the pipe 43 into the atmosphere.

' The flow of gas from the pipe 43 thus provides the pressure can bedirected into the pipe 43, into the gauge 52, or into the extension 55,which is pipe 53 and" into the bubble glass 60. This sight or bubblegauge is provided for the purpose of determining the rate of flow orthepressure fluid into the column of mud and the gauge is bestseen-insection in Fig.8. The pipe 53 is connected to the inlet on thebackside of the gauge scribed. This valve member is seen insection maybe observed by the bubbles passing through and the pressure fluid thusenteringthe device will discharge from the open pipe 5| into the upperchamber 62 of the gauge. A .passage 53 through the central body 64 ofthe gauge in turn discharges the fluid from the lower pipe 65 into abody 56 of suitable liquid so that any pressure fluid dischargingthrough the device will bubble up. through the liquid 65 and the rate offlow this liquid.

The pressure fluid passing through the liquid 66 will enter the pipe 61vand discharge into the low pressure pipe 58', which extends from thebubble gauge 60 downwardly to the elevation of the lower end thereof at59 in the tank 5.

this manner pressure fluid will be forced from pipe and throughthe-valve to exhaust into the lower end 63 of the pipe and the pressurere-. .quired to eflect such a continuous discharge will be eitherindicated or recorded. upon the gauge 10 shown generally in Fig. 12.This pressure is conveyed from the glass 50 by means-of aconduitor-coupling 1|, whichis connected to the body 64 of the gauge, as seenin Fig. 8.

Particular attention is directed to the fact that the pipes SI, 65 and51 are all curved so that the ends thereof are approximately in avertical plane v which is midway b'etweemthe sides of the gauge. In thismanner if-the gauge is laid on its side the liquid 85 willberetained-therein and will not flow through any one of these pipes. Theupper chamber 52 is provided so that if there is a back pressure on thepipe 68 sufllcient to force 4 the liquid upwardly through the pipe 65 itwill the power for actuating the valves to control the trapping anddischarging of the body of liquid in the container!) whosespeciflcgravity is to be determined. This supply of gas'is-directed intothe valve l3 from a'pressure reducer 50, which receives its supply ofgas from the inlet pipe line 5|. :While gas has been used as the term todescribe the fluid under pressure which is used to, actuate ,the deviceit is to be understood that compressed air or any other suitable fluidmaybe used for this purpose.

The pressure reducer 53 may be of any desired type'so as to reduce thepressure from the source in the pipe 5| to the. pipe 43. In actualpractice it has been Ioundthat a pressure of approximately twenty poundsper square inch in the pipe 43 is suflicient for operation of themechanism, whereas if gas pressure to be found in the oil flelds isutilized it is not uncommon to have a pressure in excess of onehundredpounds per square inch in the pipe 5|'.- 'A gauge 52 in Fig. 1

indicates the pressure which is present beyond the pressure reducer 5|andwhich is flowing not escape through the pipe 5| but will merelyaccumulate in the'top chamber until such pressureis reduced. As seen-inFig. 1,. the gauge is uspended on a shelf 13, which is carried by thedevice. It seems obvious that by adjusting the valve 53 any desired rateofflow may be introduced into the low pressure pipe.

. A valve-30 is similar to thevalve "and controls the-rate of flow ofthe fluid through a second sight gauge 5|, which will be known as thehigh pressure gauge because it controls the rate of flow through thehigh pressure line 82 by which the flow of fiuidis introduced into thelower portion of. the container 5 where thefluid pressure dischargesfrom the'lower end 33 of the line 32. By manipulation or arrangementofthe valve 3|! any desired rate of flow may be provided through thispipe.

'It seems obvious that, inasmuch as the distance between the lower endof the low pressure pipe at II and thelower end of the high pressurepipe at is a fixed distance,'/th,ere will be a diflerential pressurewhich isthe diiierence betweernthe pressure required to force the flowof fluid through the high pressure pipe 82 and the pressure required' toforce the fluid through the low pressure pipe 68. This difierentialpressure can be measured and will, of course, vary with the specificgravity of the liquid which is in the container 5. If the liquidisheavier a greater differential pressure will be required. If the liquidis fighter a lesser diiierential pressure will be required. In Fig. 12the gauge line 84 extends from the sight gauge 8| the same as explainedin connection with the line 1|. The recording meter 10 in Fig. 12 willrecord the diflerential pressure and as seen by the recording line 85the pressure drops down materially when the container is emptied andbuilds up to a maximum point when the container is filled. Therefore,the maximum radial distance which the recording line reaches, as at 86,when the tank is fllled will indicate the specific gravity of the liquidwhich fills the container. The gauge 10 may be so calibrated that thisrecording will be either in pounds per gallon or may be otherwisesuitably calibrated.

In actual practice it has been found that the discharge of a fluid underpressure from the pipes 68 and 82 causes an evaporation at the point ofdischarge such as 69 and 83. This evaporation dries the drilling mud andforms a cake or nozzle about the ends of the pipe and it has thereforebeen found to be desirable to lubricate the fluid 'under pressure whichis being introduced into the device and to this end a tank 90 carries abody of 7 water or other liquid 9 I, which can be fed through the pipe92 into a lubricator injector 94, which in turn discharges through thepipe 95' into a connection 96' so that there is a. small flow of liquiddownwardly through thepipe 82, as best seen in Fig. 3.

The regulator or injector 94 may be so adjusted as to permit apredetermined flow. In order that .the liquid 9 will be forced into thepipe 82 with suificient pressure to overcome the back pres-- sure due tothe head of liquid in the containerB a supply of pressure fluid isintroduced into the tank 90 by means of the connection 95. Thisconnection has a gauge 96 thereon and receives a flow of gas from theregulator 91, which in turn receives its flow of pressure fluid from theconnection 55 through the cross 53. This regulator 51 may be set for avery low pressure, say five pounds per' square inch, if the regulator 50is set and which will be a compact self-contained unit adapted to bereadily connected for use at a drilling rig.

What is claimed is:

1. A specific gravity measuring device for drilling mu-ds includingmeans to determine the differential pressurerequired to pass a flow offluid into a body of mud, as an indication of the specific gravity ofsuch mud, and additional means operable by the mud to effect thedischarge and admission of the mud.

2. A device of the character described comprising a container, means toadmit and discharge rotary drilling mud adjacent the top of and adjacentthe bottom respectively of said container, means operable by theadmission and discharge of mud to actuate said first means so that saiddevice operates automatically to admit and discharge drilling mud, meansto continuously effect a flow. of fluid into said container at spacedelevations, and additional means to indicate the differential pressurerequired to maintain such flow of fluid as an indication of the specificgravity of the drilling mud which is in the container.

3. A device of the character described comprising a container, means toadmit and discharge rotary drilling mud adjacent the top of and adjacentthe bottom respectively of said container, means operable by theadmission and discharge. of mud to actuate said first means so that saiddevice operates automatically to admit and discharge drilling mud, meansto continuously efiect a flow of fluid into said container at spacedelevations, and additional means to indicate the differential pressurerequired to maintain such flow of fluid as an indication of the specificgravity of the drilling mud which at twenty pounds per square inch. Asimilar luity of the drilling fluid which is flowing through the pipe 2and the operator need onlyobserve the gauge 10 in order to'determinethat the Specific gravity of his mud as it returns from the well bore iswithin predetermined limits. In event the mud becomes gas-cut thespecific gravity will be reduced and the operator will observe thischange.' The same applies to other factors, which influence the'speciflcgravity of the mud.

Broadly the inventioncontemplates a device which will operateautomatically to periodically determine the specific gravity of adrilling mud,

is in the container, said flow means including a bubble glass. 4

- 4. A device of the character described comprising a container, meansto admit and discharge rotary drilling mud adjacent the top and adjacentthe bottom respectively of said container, -means operable by theadmission and discharge of mud to actuate said first means so that saiddevice operates automatically to admit and dischargev drilling mud,means to continuously efiect a flow of fluid into said container atspaced elevations, and additional means 'to indicate the 'difierentialpressure required to maintain such flow of fluid as an indication of thespecific gravity of the drilling mud which is in the container, saidvadditional means including a recording differential pressure gauge.

5. In a device for measuring specific gravity of a drilling mud, ameansto introduce fluid into the body of drilling mud so that the pressurerequired for suchintroduction may be determined as an indication of thespecific gravity, said means including a bubble glass including a topand a bottom, and curved inlet and outlet pipes for the flow of fluid,the ends of said pipes being along the axis of said glass so thattiltingthereof will not discharge I the liquid therefromr 6. A device fordetermining the specific gravity of a, drilling mud, means to connectthe device toperiodically receive adjacent the top and dischargeadjacent the bottom a quantity of drilling mud so that the mud may flowby gravity,

diflerential pressure between. two vertically spaced points in thedrilling mud.

7. A device for determining the specific grav-" ity of a drilling mud,means to connect the device to periodically receive adjacent the top anddischarge adjacent the bottom a quantity of drilling mud so that the mudmay flow by gravity, and

means to periodically indicate the specific grav-.. ity of the mud whenthe device contains a predetermined volume of' mud, both of said meansbeing operable from a source of fluid under pressure. a

8. In a specific gravity measuring device, a

container, means to admit and discharge liquid whose specific gravity isbeing determined to the top and from the bottom respectively of saidcontainer, float means in said container and .operable by the fillingand emptying of such container, and fluid pressure power operated meansconnected to said float means to operate said first means, andadditional means to continuously inject two streams of fluid underpressure into the varying head of liquid in the container at spacedelevations, and means to determine the presmre diflerential to effectsuch the difl'erential pressure required to efl'ect discharge is afunction of the specific gravity of the mud in the container while themud between the ends of the members is dormant, and

means to discharge the mud when the level in so the container reaches apredetermined position.

JOHN B. WARREN, JR.

